The main objective of this research program is to determine the role of the plasma membrane in the control of motility and metabolism in human spermatozoa. The experimental approach will involve the use of certain membrane-active compounds and their antagonists to control the initiation and inhibition of motility. The effect of these drugs on ion transport, carbohydrate transport, membrane structure and energy metabolism will be studied. This will be supplemented by other experiments which will probe the effects of these drugs on the enzyme activity (particularly cation activated ATPases and adenyl cyclase) and cation binding capacity of isolated plasma membrane preparations. A practical objective of this proposal is to test a vaieity of pharmacological agents with a view to their potential use as spermicidal contraceptives.